An article in the Journal of Manufacturing Systems (1991, vol. 10, pp. 32€“40) described an experiment to investigate the effect of four factors, P = waterjet pressure, F = abrasive flow rate, G = abrasive grain size, and V = jet traverse speed, on the surface roughness of a waterjet cutter. A 24 design follows. 

(a) Estimate the factor effects.

(b) Form a tentative model by examining a normal probability plot of the effects.

(c) Is the model in part (b) a reasonable description of the process? Is lack of fit significant? Use a = 0.05.

(d) Interpret the results of this experiment.

(e) Analyze the residuals from this experiment.

Transcribed Image Text:

Factors Surface Roughness (µm) Run (in/min) (Ib/min) (kpsi) (Mesh No.) 1 6. 2.0 38 80 104 2 2.0 38 80 98 3 2.0 30 80 103 30 4 2 2.0 80 96 5 6. 1.0 38 80 137 1.0 38 80 112 6. 1.0 30 80 143 8. 1.0 30 80 129 170 6. 2.0 38 88 10 2 2.0 38 170 70 11 6. 2.0 30 170 110 12 2 2.0 30 170 110 13 1.0 38 170 102 14 2 1.0 38 170 76 15 6. 1.0 30 170 98 16 1.0 30 170 68 2.